Fabric dryer with lint burning means



Nov. 6, 1962 p. w. SCOFIELD 3,061,942

FABRIC DRYER WITH LINT BURNING MEANS Filed Dec. so, 1958 INVENTOR.

00/1/1910 14/. .S'Cflf/EZD United States Patent Orifice 3,061,942Patented Nov. 6, 1962 3,061,942 FABRIC DRYER WITH LlNT BURNING MEANSDonald W. Scofield, Glenside, Pa., assignor, by niesne assignments, toPhilco Corporation, Philadelphia, Pa., a corporation of Delaware FiledDec. 30, 1958, Ser. No. 783,744 6 Claims. (Cl. 3482) The presentinvention relates to laundry apparatus. More specifically the inventionhas to do with apparatus of the kind in which provision is made to dryclothes and which is devised especially, although not exclusively, forhome usage.

In most apparatus of the above mentioned variety, the drying of theclothes is generally accomplished by circulation of heated air within anenclosure in which wet or damp clothes are tumbled or otherwise agitatedto effect transfer of moisture to the circulated air. However, in suchmachines, the circulating air also picks up lint which forms during thedrying process, and it is common practice to mount a trap in the passagewhich leads to the outside of the clothes-containing enclosure tointercept and remove lint from the air passing through said passage.Such a trap tends to become clogged with accumulated lint which resultsin deleteriously affecting the drying operation and gives rise to firehazards.

It is therefore an important object of this invention to overcome theabove noted undesirable features and to insure safety in the use of aclothes-drying machine by lessening the possibilities of undue anddangerous accumulation of lint in the air-circulating passages of themachine.

A characteristic feature of the invention resides in the provision of aclothes-drying machine wherein lint which accumulates therein isautomatically eliminated at the end of each use.

It is also a characteristic feature of the invention to disposed ofaccumulated lint by burning the same, provision being made to eliminateserious objections which might arise from burning of the lint.

According to one aspect of the present invention, the above notedobjects and novel features are achieved by utilization of a machinecomprising an enclosure for containing clothes to be dried, saidenclosure being associated with a heater and with air-circulating meansto direct the flow of air into and out of said enclosure. Delintingmeans is arranged in the air-circulating means to trap lint entrained inmoist air which flows from the drying enclosure. In particularaccordance with the invention, the delinting means includes a novelcombination of lint-burning means and vapor-treating means. Thelintburning means is adapted to ignite accumulated lint at thecompletion of the drying operation, and the vaportreating means isadapted to eliminate the smoke together with the odors resulting fromburning of the lint. Also, in particular accordance with the invention,a control arrangement is provided for automatically effecting theoperation of the machine as well as of the lint-burning means andvapor-treating means. This control arrangement includes electricalconnections and switch means, the latter functioning automatically,first to interrupt the operation of the driving motor for the machine,then to initiate operation of the vapor-treating means to place the samein operative condition, and thereafter to activate the burning means forigniting the lint trapped in the delinting means during the dryingprocess.

The full nature of the invention and the manner in which the abovementioned and other objects and features are realized will be more fullyunderstood from the following description taken in conjunction with theaccompanying drawing, in which:

FIGURE 1 is a vertical sectional view of a laundering machine whichincludes a preferred embodiment of the present invention, certain partsbeing broken away and removed for purpose of clear illustration.

FIGURE 2 is a fragmentary view, in perspective and on an enlarged scale,showing that portion of the air exhansting duct or passage whichencloses the lint intercepting and burning device of the embodimentillustrated in FIGURE 1;

FIGURE 3 is a sectional view, on a still larger scale, takensubstantially on line 33 of FIGURE 2; and

FIGURE 4 is a diagrammatic view illustrating an arrangement of electriccircuits and means for controlling the operation of the launderingapparatus as well as of various elements included in the preferredembodiment of the invention.

With more particular reference to the drawing, there is shown in FIGURE1 those parts of a laundry apparatus which are essential to a clearunderstanding of the invention. As illustrated, the machine includes acabinet structure It} which encloses a drying enclosure or com partmentill configured to house a clothes-containing receptacle 12 in the formof a perforated drum. This drum is mounted to rotate about a generallyhorizontal center axis 13, and has an open front 14 through whichclothes may be placed into and removed from the machine. This open frontis disposed to confront the con ventional sealing door, not shown, whichis usually hinged on the cabinet structure of the machine.

An electric motor 15 is conveniently mounted within the cabinet 10 androtatably drives the drum at required speed through the intermediationof belts 16 and pulleys 17. The motor is adapted to be controlled bymeans of a timer and switching mechanism 18 having a manually operablesetting knob 19, and driven, as is customary, by means of a spring motor18a.

Air-circulating means including a blower or fan 20 driven by the motor15 through a belt 21, or like connection, effects flow of air throughthe dryer. As represented by the flow arrows in FIGURE I of the drawing,air is admitted into the interior of the dryer through inlet means 22and enters the drying enclosure or compartment 11 through intakepassages 23. Air circulating within said enclosure passes into and outof the drum through its perforations 24 and, thus, flows in contact withthe clothes as they tumble in said drum. The walls of the enclosure andof the drum, as well as the air circulating through the machine, areheated and brought to drying temperatures by means of a heater 25. Asdiagrammatically represented in the drawing, the heater is of theelectrical resistance type and is conveniently mounted so that the airis heated by coming in heat exchange relation with the walls enclosingsaid heater. From the drying enclosure, air passes into an outletpassage 26 which opens out of a lower part of said enclosure andcommunicates with the inlet side of the blower 20 through an intake duct27, the outlet side of the blower communicating with a discharge duct28.

The heated air passing through the drum, in the manner described above,picks up and carries away moisture from the clothes thereby drying thesame. Lint which forms in the clothes-drying process is also carriedaway or entrained in the air passing out of said enclosure. However,lint is prevented from escaping through the blower 20 and discharge duct28, by means of a lint collecting or trapping device designated at 29and located in the intake duct 27, between the outlet passage 26 and thefan or blower 20.

As clearly seen in FIGURES 2 and 3, the device 29 includes a screenelement 30 which, in practice, is adapted to constitute a lint burner.For that purpose the screen is woven from electrical resistance wire ofhigh heat generating and retaining properties, such as wire of anickelchromium alloy, for example the alloy known as Nichrome. Thisscreen element 39 is welded or otherwise securely aflixed to a pair ofrugged metal members which form terminals 31, the assembled screen andterminal members being mounted on an insulating support, such as a slab32 of asbestos or like material, which occupies and spans the interiorof the intake duct 27. The insulating slab is provided with a centrallydisposed open area or window 33 which is covered by the mentioned screenelement 30. Air circulating through the intake duct 27 flows through thescreen, and the lint entrained in said air is intercepted by andaccumulates on said screen.

As will be hereinafter more fully described, at the proper time in thesequence of operation of the apparatus electric current is supplied tothe burner assembly so as to heat the screen and thereby ignite the lintaccumulated thereon.

In particular accordance to the invention, the vapor resulting fromburning lint is passed through a treating chamber 35 which is adapted todestroy smoke and odors. According to the preferred embodiment of theinvention, the treating chamber encloses a catalytic incinerating unit35a which, itself, forms no part of the present invention and thus neednot be described in detail herein. How ever it may here be mentionedthat a unit suitable for the purpose of the invention is one of wellknown type which utilizes a plurality of electrically heated coils eachcoated with a suitable catalyst, for example platinum, and having ohmicresistance such that when the coils are energized by a suitable sourceof electric current, they are maintained at the elevated temperaturerequired for satisfactory activation of the catalyst to render smoke andodors undetectable.

As illustrated, the chamber 35 enclosing the catalytic unit is definedby conduit structure which provides an inlet conduit 36 and an outletconduit 37 leading, respectively, into and out of said chamber. Theinlet conduit 36 communicates with the interior of the air intake duct27 and, for that purpose, has an inlet end portion 38 constructed to fitsnugly in an opening 39 which, as clearly seen in FIGURE 2, is disposedadjacent the screen-burner device 29 within said duct 27. As shown, theopening 39 and associated inlet end portion 38 of the inlet conduit 36are positioned above and straddle said device 29 so that all the smokearising from the burning lint tends to pass directly into said conduit,thence through the treating chamber 35.

In the illustrated arrangement, the screen-burner element 30 is made upof a plurality of comparatively short wires connected in parallel, sothat the element has low electrical resistance. In order to insureadequate heating of this kind of element to ignite and burn lint, thereis provided a transformer 40 connected with the terminal members 31 ofsaid screen element in a manner to supply it with high current atreduced voltage. It will of course be understood that a transformerwould not be needed if certain types of burner elements were employed.For example, an arrangement constructed with serpentine or coiled wiresconnected in series would have high electrical resistance, so thatcurrent could be supplied thereto at the customary 110-120 V. linevoltage.

The manner in which the illustrated and herein de scribed preferredembodiment operates will be more fully understood by referring to FIGURE4 in which the motor 15, the, clothes-drying heater 25, thescreen-burner unit 29 with its transformer 40, and the treating chamber35 with the catalytic unit 35a enclosed therein, are diagrammaticallyrepresented. These elements are adapted for electrical connection acrosspower line L L through the agency of the switch 18. As represented, thementioned elements are connected in parallel to one side L of the lineand to switch strips: the motor 15 being connected to switch strip 42;the dryer heater 25 being connected to switch strip 43; the primary ofthe transformer 40 being connected to switch strip 44; and the catalyticunit 35a being connected to switch strip 45. A switching contact arm 46is connected to the other side L of the line and is disposed to engagethe contact strips to close the electrical circuit to the variousmentioned elements in the appropriate sequence, which will be presentlydescribed.

In using the apparatus, clothes are placed in the receptacle or drum 12,and the control knob 19 is set to On position. This setting brings theswitching arm 46 (FIG- URE 4) in engagement with the contact strips 42and 43 to effect energization of the motor 15 and heater 25. Thus themotor drives the clothes-containing drum for tumbling the clothes andactivates the blower or fan 20 for circulating air through the dryingenclosure, and the heater is energized to effect drying of the clothes.

Through continued function of the timer 18a, the contact arm 46 isbrought to a position represented at A. In this position the contact armbreaks electrical contact with the strips 42 and 43, and thusdeenergizes the motor 15 and the heater 25 to stop rotation of the drumand activation of the fan, and to terminate the drying function of themachine. At that point in the sequence of operation, the timer 18a movescontact arm 46 into engagement with the contact strip 45 to energize thecatalytic unit 35a. This condition of operation continues until saidunit attains the temperature necessary to produce the desired catalyticaction. The time required to obtain that condition is determined by thetime it takes for the switching arm to travel from position A toposition B in response to operation of the timer 18a.

When the proper catalytic condition is obtained, the contact arm 46engages the contact strip 44 to effect energization of the transformer40 which, in turn, energizes the screen-burner element 30, the latterelectrically linked to the secondary of said transformer. The energizedburner element ignites the accumulated lint and causes it to burn, anydisagreeably odorous smoke resulting from the burning lint passing intothe chamber 35 and being treated therein to eliminate the odors andsmoke prior to discharge of the vapors through the outlet conduit 37.Concurrent operation of the lint-burning element and of thevapor-treating unit continues for a predetermined period of time whichcorresponds to the time it takes the timer-controlled switching arm 46to travel the distance between position B to position C.

Upon reaching said position C, the contact arm 46 leaves contact strips43 and 45 and engages contact mem ber 42a which, as represented at 47,is electrically linked to the contact strip 42. Thus the motor 15 isagain energized to reestablish tumbling of the clothes and actuation ofthe fan for a limited time in order to provide for cooling of themachine and clothes therein. This cooling period lasts for a time whichcorresponds to the time it takes the switching arm 46 to travel fromposition C to Off position, when the entire machine shuts down.

As seen in FIGURE 1, a damper plate 48 is mounted in the fan intake duct27, and a similar damper plate 49 is mounted at the outlet end of thefan discharge duct 28. These plates are hinged so that during a dryingoperation they swing to an upper position under the force of the airdrawn through said duct 27 and duct 28 in response to the function ofthe fan 20. During burning of the lint when said fan is out ofoperation, the damper plates 48 and 49 gravitate to a lower positionrepresented in broken lines in FIGURE 1, and thus serve to prevent smokefrom back-flowing into the drying enclosure and from passing into theroom in which the machine is installed.

It will be noted that the damper plate 49 is of a size to closecompletely the outlet end of the duct 28, whereas the damper plate 48 isconstructed to provide a restricted open area 51. This restricted openarea being disposed between the inlet which communicates with the warmerinside atmosphere and the Outlet which communicates with the cooleroutside atmosphere, acts to bring about a draught or chimney effectwhich insures and enhances the flow of smoke into and through thetreating chamber 35.

Also as seen in FIGURE 1, provision is made for collecting and disposingof the ashes resulting from burning of the lint. For that purpose, adrawer or tray 50 is slidably supported beneath the screen-burner device29 to catch the ashes and to be removed for periodically emptying itscontent.

From the foregoing description, it will be appreciated that the novelarrangement of this invention effectively provides for automaticdisposal of lint which accumulates as a result of a clothes-dryingoperation. Although the invention has been shown and described withreference to a preferred embodiment, it will be recognized that theinvention is not limited to that embodiment. For instance, the machineinstead of being provided with an open system for circulating air to andfrom the outside of the cabinet, the machine could be supplied with aclosed-type system which, as well known in the art, is adapted torecirculate the air through the drying enclosme, the air being cooledand dried prior to its return to said enclosure. It is to be understoodthat the invention contemplates such other structural variations as comewithin the scope of the subjoined claims.

I claim:

1. A fabric dryer comprising a drying enclosure provided with air inletmeans and with an air outlet passage, a fan operable for circulating airthrough said enclosure and having an air discharge duct and an airintake duct, the latter communicating with said air outlet passage, alint collecting device mounted in said intake duct and having meansoperable for burning the collected lint, conduit structure having aninlet end portion communicating with said intake duct adjacent to andabove said device to carry off the products of combustion from saidburning means, damper means interposed in the path of air circulatingthrough said ducts and mounted for movement to and from an operativeposition wherein said damper means impedes the flow of air through saidducts and device, said damper means being movable from said position inresponse to air velocity during operation of said fan and being movableto said position when said fan is not operating and control mechanismhaving means for terminating the operation of said fan and thereafterinitiating operation of said burning means.

2. A fabric dryer as set forth in claim 1, in which the mentioned dampermeans includes two damper plates, one of said plates being disposed inthe mentioned discharge duct, the other of said plates being disposed inthe mentioned intake duct between the mentioned outlet passage of thedrying enclosure and the mentioned inlet end portion of the conduitstructure, said other plate being constructed to provide a restrictedopen area between said outlet passage and said inlet end portion.

3. A fabric dryer as set forth in claim 1, in which means operable foraltering the mentioned products of combustion is incorporated in thementioned conduit structure.

4. A fabric dryer as set forth in claim 1, in which means operable foraltering the mentioned products of combustion is incorporated in thementioned conduit structure, the mentioned control mechanism havingmeans for initiating operation of said altering means concurrently withtermination of the operation of the mentioned fan.

5. A fabric dryer as set forth in claim 1, in which a heater is arrangedin the mentioned drying enclosure to heat the air circulatingtherethrough, means for altering the mentioned products of combustion isincorporated in the mentioned conduit structure, the mentioned controlmechanism having means for initiating operation of said altering meansconcurrently with termination of the operation of said heater and of thementioned fan and prior to initiation of the operation of the mentionedburning means.

6. A fabric dryer as set forth in claim 1, in which a fabric-containingdrum is rotatably mounted in the mentioned drying enclosure, an electricmotor is drivingly coupled to said drum and to the mentioned fan, anelectrically controlled heater is arranged in the mentioned dryingenclosure to heat the air circulating therethrough, electricallyoperable means for altering the mentioned products of combustion isprovided in the mentioned conduit structure, and the mentioned controlmechanism includes a sequentially operated time switch for firstenergizing said motor and heater then concurrently deenergizing saidmotor and heater and energizing said altering means, thereafterenergizing said burning means while continuing energization of saidaltering means, subse quently effecting concurrent deenergization ofsaid altering means and burning means and energization of said motor tooperate said drum and fan for a limited time to provide for cooling ofsaid enclosure and drum, and finally effecting complete shutdown of thedryer.

References Cited in the file of this patent UNITED STATES PATENTS839,797 Wood Dec. 25, 1906 2,809,025 Pettyjohn Oct. 8, 1957 2,925,664Cobb et a1 Feb. 23, 1960 FOREIGN PATENTS 620,906 Great Britain Mar. 31,1949

